Most people are in tune with the concepts of shield from sun in summer and warm from sun in winter - the proviso about winter is you experience weather cold enough to need some extra heat.
I have insulated in the roof recently - I expected to get a warmer winter over night and possibly hotter during summer overnight. Why? well we mostly do without A/C - we have a frequent sea breeze. Once it stops outside becomes cooler than inside - prior to insulating - the heat loss through the cielings overnight meant a cooler house come morning - now - it is still hot - so one of the few reasons to say role on winter. 
Well I guess we have really good ventilation, right on the beach, southerly windows open right into the "Dr", security flyscreen on the back door (south facing). Highest point of the house has hoppers opening to the north, if there's not enough wind we get a convection effect as well. House usually cools down to within a few degrees of outside minimum temperature.
yes the other houses in the street are really bad!!! 
that's project homes for you. typically they are all the same, a maze of hallways with no cross ventilation and all single story so the 1800 high paling fence kills any breeze, or 2 storey with the bedrooms all upstairs where the breeze is instead of the living space. some of them even have the living space facing west...... 
anyways,
as was said previously by notwal, colour is taken into account when setting an insulative value.
without going overboard,
lets look at an example of a house with north facing glass along the "full facade". it has been designed with the appropriate overhang for the glass height and so one.
old school says that's a great outcome and would give it a big tick.
but new school would give that a fail because of heat loss due to the amount of glass in almost all areas of australia other than the tropics.
it's too simplistic to say a building won't perform if it doesn't have a light coloured roof and overhangs. it's a system and there are so many products and design options available for a 3 dimensional building.
orientating the house to the north and designing the correct overhang or awning is a good start but it only looks at one end of the spectrum.
So are you saying, there's enough insulation in the ceiling and whirly birds to cope with the heat from the black roof?
And your curtains control the big eastern glass???
Cause once the heat's inside the windows, it's very hard to stop it getting into the rest of the house.
where as once the heat's in, it's not so hard stopping it from getting out. (it radiates and conducts in, but it only conducts out, that's how a glass house works)
And only 50% of the North wall needs to be glass, unless you're in Tassy, or up a mountain.
OK so you may be able to go against the "old school" and get a building that works, but it's going to have to be more complicated and more expensive to do so.
Seems to me old school is simple and easy, fair enough there is more to getting the best results than just orientation, and correct eaves and insulation. the building, it's location, occupants lifestyle, and a whole host of factors need to be taken into account.
But giving the general public, the idea that you can have a black roof and no overhangs with lots of eastern and/or western glass, is highly irresponsible.
Maybe you can do it somehow, but without giving all the does and don'ts that make it possible, people are going to end up with an extremely uncomfortable house, with huge electricity bills.
This may come as a shock to you guys, but some of us (in Vic) welcome dark roofs!
Living in a cool-temperate climate, I have a house with a dark blue roof & it helps as heating is our main focus, although I doubt it makes much diff as we have insulated our ceiling well.
We've renovated a house that faces primarily south-east, with all the bedrooms on the north (generally a design no-no), but the original builder in the 50's were focused on the view & not energy efficiency. We've added a 2nd storey onto it, and due to overlooking issues, chose to have smaller windows to the north adjoining boundary. I found that we have no need for AC, although we use it maybe 3 times a year, in the 40+deg consecutive days, which we only get a few of each year, and as Gestalt said, with cross-ventilation, a 30-35deg day is highly managable.
Because of the mass on the ground floor, no cooling is ever needed, and we've installed heavy curtains in the bedrooms (also have eaves) to combat summer heat, and in winter, the bedrooms are naturally heated, so we just need to heat the main lower living area. We rarely use heating upstairs too...ceiling fan set to reverse draws all the heat up & moves it down around the outside of the room.
Because we have a large roofspace still, I'm looking into installing a PV 'sunlizard' system to heat the house in the future (deliberately loaded insulation on ceiling & only used sisalation under iron roof so that the roofspace would provide heat in future)...now, if only we didn't need a refrigerator, lights, kettle, PC etc. we'd be fully self-sufficient!
I have noticed that the local birds (pigeons) favour the dark roofs during the cooler months. Unfortunately they show their appreciation by crapping!
I have noticed that the local birds (pigeons) favour the dark roofs during the cooler months. Unfortunately they show their appreciation by crapping!
hi decrepit, the upstairs is lightweight so the heat can be rapidly removed with cross ventilation.
the roof is sarked, no whirly birds. topped things up with the rud free insulation 3 weeks ago and put R3.5 in the ceiling.
the glass faces east becasue that has a view. i checked this morning and by about 9am you can just start to feel the heat building. by 9.30 the sun is high enough that we open the curtains and windows on the eastern side and the heat is removed in a couple of minutes.
in winter we close the curtains on dusk and open again when going to bed and things are toasty all morning.
my house looks like your typical unattractive project home. difference is i designed it. the builder didn't have a 2 storey house in my very small budget so i designed one for them. once they had removed any detail and told me that they wouldn't build skillions we built what looked like all of the other houses only a more brutal version and of course to my floor plans, actually it's very brutal 
. they also told me i needed 200sqm total build, so i stuck a neo classic portico on the front as a bit of a piss take plus to shade the west. even put a round window in as it's near the water. (always the smart arse)
in short,
almost no west facing glass. (the street)
no hallways
complete cross flow
high mass ground floor low mass first floor
living upstairs
4 bed 2 car
polished particle board etc etc.
even when there is no breeze the smaller windows on the west side suck the air through from the big windows on the east/north
cost $130k
one regret is not having more southern windows. i reduced the amount of southern windows as the house is hard up on the southern setback and i didn't want to hear or see the neighbours. also when i say no overhangs, it has overhangs, some are 150mm and others 400mm
also in response to the comment about irresponsible to suggest black roofs are ok and overhangs are over rated. i understand your point,
but,
it's not hard to design something that works even with black roofs and no overhangs if that's what you are into. the fact that someone might take those 2 ideas and design a bad outcome is not my fault. reality is anyways, most people are going to end up with a bad outcome regardles of what i say here because they will buy a poorly designed project homes. even with overhangs and a light roof it still won't work. if they were to go to a quality architect or building designer they wouldn't get a much better outcome and it would cost more.
hey decrepit,
i thought of a better way of putting it. i should have just said this in the first place.
most house designs have more issues to worry about than whether the roof is black. just getting the basic planning right would be a start.
